Research Highlight

An online repository of breast milk contaminants

doi:10.1038/nindia.2021.45 Published online 25 March 2021

Researchers have developed an India-specific, freely accessible web resource cataloguing xenobiotics, environmental contaminants that can find their way into mother’s milk1.

The web resource, named Exposome of Human Milk across India (EXHuMId), contains 101 contaminants that include potential carcinogens, hormone disruptors and neurotoxins, researchers from the Institute of Mathematical Sciences in Chennai say.

The scientists, led by Areejit Samal, generated ExHuMId by cataloguing environmental contaminants detected across 13 states of India. They compiled the data on the contaminants from 36 studies on human milk, including details about the concentrations of the chemicals in the human milk samples, and lifestyle- and pregnancy-related factors related to the mothers.

The research detected the highest number of contaminants in samples from Tamil Nadu, followed by West Bengal. The chemicals include insecticides such as beta-hexachlorocyclohexane and lindane, both of which were detected in samples from 12 states.

Of all the contaminants, 43 block or interfere with the activities of hormones, 23 are carcinogens and 14 are toxic to the nervous system.

The contaminants, the studies show, target specific genes and proteins involved in lactation, growth, reproduction and immune responses. Among the contaminants, arsenic targets several genes involved in lactation and immune responses through its presence in human milk.

The researchers say that this can affect effective immune response in developing infants. ExHuMId, Samal says, will help set the course of future research and policy planning to monitor the harmful chemicals.


1. Karthikeyan, B. S. et al. ExHuMId: A curated resource and analysis of Exposome of Human Milk across India. Chemosphere. 271, 129583 (2021)